A while back,I reworked the brake lines on my 65 Impala
I installed new brakes lines all over and converted it to a dual master.
I bought most of my parts from In-Line Tube.
When I needed additional fittings,they had everything I needed.They have a fellow you call and actually talk to,who is very helpful and patient.
Not advertising for them,just giving a source for parts.
Mike.